196 



Family Setosellidae ' n. f. 

 Setosella Hincks. 



The zooecia the frontal wall of which is perforated by two slit-shaped opes- 

 iulse have a well chitinized simple operculum with a well developed opercular 

 arch. No spines. The lateral walls which are common to the contiguous zooecia 

 are in their distal part provided with a large membranous, uniporous (?) rosette- 

 plate. Obliquely, distally to each zooecium is found an independent vibraculum 

 without a cross-bar, with a long, strong, dentate flabellum. The ooecia are small 

 rounded cavities in the frontal wall of the arched distal part of the gonozooecium, 

 the »ooecial area«, which is distinctly separated from the lateral parts by an 

 impressed line. The ooecial cavity which is distinctly apparent on the outer sur- 

 face opens out through a hole gradually increasing in size. 



The ooecia of the present genus, which have hitherto been overlooked, belong 

 to the same division of ooecia (p. 65), the endotoichal, found in the genera Cellu- 

 laria and Membranicellaria, but while in these they are placed in the proximal 

 part of the frontal wall, they are in Setosella placed in the distal part of this 

 wall. 



While the aperture of the common zooecia is about as high as broad the 

 aperture of the gonozooecia is broader than high, with a somewhat convex proxi- 

 mal margin and with two acuminated corners. 



On account of the ooecial form I have thought it necessary to set up a new 

 family for this genus which is represented by a single species S. vulnerata Busk. 

 Of this species colonies have been taken by the Ingolf Expedition at Lat. 25" 21' N., 

 Long. 63" 21' W., at a depth of 170 fathoms. 



Family Chli'doniidae. 



The jointed colonies, springing from a stolonate network, consist of a stem, 

 two main branches and a number of zooecia-bearing secondary branches, and 

 besides the zooecia we may distinguish between three different forms of kenozocecia, 

 namely the partitions of the stolon, the stem-internodes and the bifurcate inter- 

 nodes of the main branches. Moreover, the main branches and the secondary 

 branches end in a number of small cylindrical internodes, of which those in the 

 secondary branches may be transformed into zooecia. The zooecia, which lack 

 pores and spines, have a deeply depressed cryptocyst, pierced by a small trans- 



' Neither this family nor the family Crepidacanthidae are named in the synopsis on p. 88, both 

 families having been founded later. 



